A “hundred” hospitals, according to the Ministry of Health, had to trigger their white plan this weekend, in other words recalling staff normally on leave and rescheduling operations to cope with the influx of patients. The fault is the flu, which started early this year just before Christmas and continues to gain ground. At the beginning of January, nearly 4,000 patients had to be hospitalized after presenting to the emergency room for respiratory syndromes.
If the epidemic is intense, and it causes tensions rarely seen in healthcare establishments in recent years, some specialists nevertheless refuse to qualify it as “exceptional”, at least for the moment. Like Professor Marie-Anne Rameix-Welti, head of the National Reference Center for Respiratory Infections at the Pasteur Institute in Paris. “We have already experienced episodes of flu of the same magnitude. In the city, the circulation of the virus is currently not much higher than in other years,” she notes.
An analysis shared by Professor Antoine Flahault, director of the Institute of Global Health in Geneva and specialist in influenza: “The epidemic of winter 2024-2025 resembles for the moment in every way an epidemic of one year of medium to large size, although we will of course only be able to specify this assessment after the peak, which does not yet seem to have been reached.”
Three different viruses in circulation
How can we explain, in these conditions, that hospitals are overflowing? For Marie-Anne Rameix-Welti, the explanation is more to be found in the difficulties specific to the healthcare system, combined with the early timing of the epidemic, which started just before the Christmas holidays. “During the holiday period, the relay in community medicine was perhaps a little less important. And we know that healthcare establishments were already under pressure before the arrival of the flu,” she underlines.
Because the viruses currently present in France do not present any notable particularity. “No data indicates at this stage that the circulating strains have an exacerbated virulence,” notes Antoine Flahault. Main difference with recent years: three viral strains are currently circulating, compared to two usually – two A viruses (one H1N1 and one H3N2) and one B virus. Each of these viruses attacks different age groups in the population more severely.
Type B flu is often more severe for younger people. The H1N1 virus mainly affects 18-59 year olds. As for H3N2, it causes severe forms more in elderly people, who were not exposed to it in their childhood because it appeared in the 1960s. This concomitant presence of three viruses is not, however, enough to explain the current situation. according to Marie-Anne Rameix-Welti: “H3N2 is gaining momentum, but until recent days, it circulated relatively little.”
Insufficient vaccination
Rather than the characteristics of the viruses, the insufficient vaccination of the population seems to weigh again this winter. If the figures are missing because the campaign is not yet over, The Parisian indicated in mid-November that the number of doses delivered to pharmacies was falling – 5.9 million doses compared to 6.7 million a year earlier. From one year to the next, the share of the immunized population, including among populations at risk, continues to erode.
Regrettable, since so far the vaccine seems rather protective. “The first, still very preliminary, data show that it prevents infection in 40% of immunized people,” specifies Marie-Anne Rameix-Welti. We know that these performances vary every year. But this winter, the strains selected correspond to the viruses in circulation. At least for the moment, because the H3N2 vaccine strain seems a little less suitable: if this virus were to take up more space, this could degrade the effectiveness of the vaccine.
However, it is impossible to know how the epidemic will evolve in the coming days and weeks. Many factors come into play. The return of children to school, the traditional driver of epidemics. The weather, the cold being more favorable to the virus. “The B virus could disappear more quickly than in other years, and give a shorter epidemic, H3N2 could gain momentum… with influenza viruses, we can expect anything,” summarizes Professor Rameix-Welti. One thing is certain: there is still time to get vaccinated to protect yourself from a disease that we too often forget can be severe. Even lethal.
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